Surface of a concrete block



FIG. 1 is a front perspective view of a surface of a concrete blockaccording to a first embodiment of the present design;

FIG. 2 is a front view of the concrete block surface of FIG. 1;

FIG. 3 is a front perspective view of a surface of a concrete blockaccording to a second embodiment of the present design; and,

FIG. 4 is a front view of the concrete block surface of FIG. 3.

The broken lines in the drawing views are included for the purpose ofillustrating portions of the concrete block that form no part of theclaimed design.

I claim the ornamental design for a surface of a concrete block, asshown and described.